RIX sham and cultural differences 2022

Stimulated by Prinsloo et al 2022.[1]

RIX – Radiotherapy-Induced Xerostomia
XQ – Xerostomia Questionnaire

key to acronyms

At the end of 2019 a large, 2-centre, 3-arm study was published of acupuncture for prevention of RIX.[2] It was the first large (n=399) clinical trial in RIX, the first trial that performed the acupuncture from the start of radiotherapy, and the first acupuncture trial to include a centre in both China (Fudan University Cancer Centre, Shanghai) and the US (MD Anderson Cancer Centre, Texas). I highlighted this study on the blog previously: RIX sham and cultural differences.

The acupuncture protocol included one point on the face (CV24), 3 in the limbs (LU7, KI6, GB32) and 4 ear points. Treatment was performed 3 times a week for 6 to 7 weeks on the same days as radiotherapy.

A slightly unusual part of the protocol was to perform real needling at GB32 on the right side in the sham group and non-penetrating sham needling (using the Park sham device) at GB32 on the right side in the real acupuncture group. There was also real needling in the sham group at 4 points on the helix of each ear.

The results (XQ) showed an effect of acupuncture over standard care but not over sham. There were differences between centres with the sham results looking the same in both, but the acupuncture and standard care results were about 10 points higher (worse) in Texas compared with Shanghai. As a result, there was little difference between real acupuncture and sham in Texas and little difference between sham and standard care in Shanghai, but significant differences between real acupuncture and standard care in both centres and between real acupuncture and sham in Shanghai only.

The study I saw recently is a small pilot study on 13 of the patients from Texas and 14 from Shanghai. EEG was performed during real acupuncture and sham at different times and the results were analysed with a system (algorithm) called LORETA.

LORETA uses the data from the surface EEG electrodes to infer what is happening deeper in the brain as well as the cortical layers. Differences were found that might help to explain the different responses in the larger trial, but the findings are necessarily rather speculative.

The EEG during sham acupuncture, which included real needling of one body point (right GB32) and 8 points on the helix of the ears, was subtracted from the EEG during real needling for each individual patient, and the remaining activity was analysed. Most of this remaining activity was in the delta (0.5–3.5Hz) and alpha (8–12Hz) bandwidths. Delta is associated with slow-wave sleep and alpha with awake relaxation.

In the patients from Shanghai, the differences in EEG between real and sham were in regions previously associated with real acupuncture, but in the patients from Texas the biggest differences were in areas that usually decrease in activity with real acupuncture. In these regions, the difference was much bigger in the Shanghai patients compared with those from Texas.

It is almost as if the brains of the patients from China found it easier to get into the real acupuncture zone, but those from the US were a bit less certain of the difference between real and sham. More details, colour and Brodmann areas at the webinar tonight – come with your best beta bandwidths ie awake and concentrating ;-).


1          Prinsloo S, Rosenthal DI, Garcia MK, et al. Cross-Cultural Brain Activity Differences Between True and Sham Acupuncture for Xerostomia During Head and Neck Cancer Radiotherapy. Integr Cancer Ther 2022;21:15347354221101630. doi:10.1177/15347354221101630

2          Garcia MK, Meng Z, Rosenthal DI, et al. Effect of True and Sham Acupuncture on Radiation-Induced Xerostomia Among Patients With Head and Neck Cancer: A Randomized Clinical Trial. JAMA Netw Open 2019;2:e1916910. doi:10.1001/jamanetworkopen.2019.16910

Declaration of interests MC